MOSCOW/WASHINGTON, Nov 14 (Reuters) - Russia's Defence Ministry said on Tuesday an employee had attached the wrong photos to a statement accusing the United States of providing de-facto air cover for Islamic State in Syria after the mistake was spotted online.

The ministry said it would investigate the incident, which it said was caused by a civilian employee, but did not say how or why the pictures used were incorrect.

"However, the U.S. command's refusal to carry out strikes on the convoys of ISIL terrorists retreating from Albu Kamal on November 9 is an objective fact reflected in the transcripts of the talks and therefore, fully known to the U.S. side," Interfax news agency quoted the ministry as saying on Tuesday.

Earlier on Tuesday, the ministry posted a statement on its Facebook page saying the U.S. air force had tried to hinder Russian strikes on Islamic State militants, accompanied by satellite photographs it said showed a vehicle convoy of Islamic State militants leaving the Syrian town of Albu Kamal on Nov. 9 2017.

At least one of the photographs exactly matched a frame from a promotional video for a "AC-130 Gunship Simulator" computer game posted online in March 2015.

Asked about Russian allegations of the U.S. helping Islamic State around Albu Kamal, Colonel Ryan Dillon, spokesman for the U.S.-led coalition fighting Islamic State, said: "The Russian ministry of defense statements are about as accurate as their air campaign and I think that is a reason for them to start, you know, coming out with their latest barrage of lies."

"I certainly can't verify, but I've seen the report that one of the pictures came from a video game. So, again that is pretty consistent with what we have seen come out of Russian MoD, as being baseless, inaccurate and you know, completely false," he told a briefing with Pentagon reporters on Tuesday. (Reporting by Jack Stubbs, Phil Stewart and Idrees Ali; writing by Polina Devitt)